A green and economical MgO/biochar composite for the removal of U(VI) from aqueous solutions

A magnesium oxide/biochar (MgO/biochar) composite, which was green and economical compared with numerous materials, was synthesized by a facile method. And MgO/biochar performed excellent adsorption ability in the sequestration of U(VI) with the satisfied maximum adsorption capacity (514.72 mg g−1) at pH = 4.0, m/V = 0.2 g L−1, CU(VI)initial = 10 mg L−1, I = 0.01 M NaNO3, T = 298 K. The morphology, spectroscopic properties, chemical composition, etc. of MgO/biochar were characterized systemically by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), Fourier transform infrared (FTIR). The batch experiments showed that the adsorption process was predominated by pseudo-second-order rate model and the adsorption isotherm conformed to the Langmuir model. The prepared MgO/biochar exhibited commendable U(VI) adsorption performance in a wide pH range. X-ray photoelectron spectroscopy (XPS) analysis suggested that the interactions between U(VI) and the hydroxyl groups on the surface of the MgO/biochar contribute greatly to the efficient adsorption process. This work underlines new opportunities in combining the advantages of MgO and biochar, and further broadens new horizons of separating pollutants from the aquatic environment by an environment-friendly materials.